AIDS drugs show promise at preventing infection

Atlanta  Twenty-five years after the first AIDS cases jolted the world, scientists think they soon may have a pill that people could take to keep from getting the virus that causes the global killer.

Two drugs already used to treat HIV infection have shown such promise at preventing it in monkeys that officials last week said they would expand early tests in healthy high-risk men and women around the world.

"This is the first thing I've seen at this point that I think really could have a prevention impact," said Thomas Folks, a federal scientist since the earliest days of AIDS. "If it works, it could be distributed quickly and could blunt the epidemic."

Condoms and counseling alone have not been enough - HIV spreads to 10 people every minute, 5 million every year. A vaccine remains the best hope but none is in sight.

If larger tests show the drugs work, they could be given to people at highest risk of HIV - from gay men in American cities to women in Africa who catch the virus from their partners.

People like Matthew Bell, a 32-year-old hotel manager in San Francisco who volunteered for a study of one of the drugs. "As much as I want to make the right choices all of the time, that's not the reality of it," he said of practicing safe sex. "If I thought there was a fallback parachute, a preventative, I would definitely want that."

AP Photo/Jeff Chiu

Matthew Bell, 32, a study participant for an AIDS drug that is being tested to prevent infection with HIV, poses for a photograph at his home in San Francisco, Friday, March 24, 2006. Bell is shown holding a container of pills that has a memory chip in the lid that records each time he opens it so doctors can verify when and how often he's taking the drug.

The drugs are tenofovir (Viread) and emtricitabine, or FTC (Emtriva), sold in combination as Truvada by Gilead Sciences Inc., a California company best known for inventing Tamiflu, a drug showing promise against bird flu.

Unlike vaccines, which work through the immune system - the very thing HIV destroys - AIDS drugs simply keep the virus from reproducing. They already are used to prevent infection in health care workers accidentally exposed to HIV, and in babies whose pregnant mothers receive them.

Taking them daily or weekly before exposure to the virus - the time frame isn't known yet - may keep it from taking hold, just as taking malaria drugs in advance can prevent that disease when someone is bitten by an infected mosquito, scientists believe.